Astroblog

Obscured by Clouds. The rough and ready blog of a cloud benighted biologist and amateur astronomer. Astroblog will cover my interests in astronomy, biology and Life, the Universe and Everything.

Wednesday, December 30, 2015

A cloudy ISS pass (30 December 2015)

The ISS briefly emerging from the cloud around 21:36 ACDST. The best of only 2 images I captured. Click to embiggen to see the faint track.

As there was a bright ISS pass, and the possibility of aurora, of COURSE it was clouded out. Did get a brief glimpse of the ISS through thinning cloud though, although I saw it pass under Archenar in that short time.

Catch a Bright International Space Station Pass Tonight (30 December 2015)

The ISS passes near Fomalhaut, as seen from Adelaide on the evening of Wednesday 30 December
at 21:35 ACDST. Simulated in Stellarium (the ISS will actually be a
bright dot), click to embiggen.

The ISS passes below the Southern Cross, as seen from Sydney on the evening of Wednesday 30 December
at 22:07 AEDST. Simulated in Stellarium (the ISS will actually be a
bright dot), click to embiggen.

The ISS passes below the Southern Cross, as seen from Perth on the evening of Wednesday 30 December
at 20:34 AWST. Simulated in Stellarium (the ISS will actually be a
bright dot), this is different from the Heavens Above prediction which has it above the Southern Cross. click to embiggen.

All sky chart showing local times from Heavens Above for Wednesday 30 December for Adelaide.

All sky chart showing local times from Heavens Above for Wednesday 30 December for Sydney.

All sky chart showing local times from Heavens Above for Wednesday 30 December for Perth.

Tonight there is a bright evening pass of the
International Space Station at or around nautical twilight (around an hour after sunset). For many places in Australia the ISS glides close the Southern
cross or pointers. In other places it comes close to the bright star Fomalhaut (Melbourne, Brisbane, Adelaide). Darwin sees no pass.

Example cities are below.

Time Direction Magnitude

Alice Springs ACST Maximum altitude

20:32:10

19°

224° (SW)

-0.2

Adelaide ACDST Maximum altitude

21:34:59

50°

220° (SW)

-2.3

Brisbane AEST Maximum altitude

19:29:36

48°

226° (SW)

-2.2

Melbourne AEDST Maximum altitude

22:06:36

42°

215° (SW)

-1.9

Sydney AEDST Maximum altitude

22:07:11

15°

211° (SSW)

0.1

Perth AWST Maximum altitude

20:37:11

30°

219° (SW)

-1.1

When and what you will see is VERY location dependent, so you need to use either Heavens Above or CalSky
to get site specific predictions for your location (I'm using Sydney, Adelaide and Perth as examples).

Start looking several minutes before the pass is going to start to get
yourself oriented and your eyes dark adapted. Be patient, there may be slight differences in the time of the ISS appearing due to
orbit changes not picked up by the predictions.

The Sky This Week - Thursday December 31 to Thursday January 7

The Last Quarter Moon is Saturday January 2. Earth is at perihelion. Mercury is low in the twilight
sky. Jupiter, Mars, Venus and Saturn form a line in the morning sky and are joined by the waning to crescent Moon. Venus and
Saturn come closer. On the 7th Venus, Saturn and the crescent Moon form a triangle. Comet C/2013 US10
Catalina is higher in the morning sky and comes close to the bright star Arcturus.

The Last Quarter Moon is Saturday January 2. The Moon is at apogee, when it is furthest from the Earth, at this time. Earth is at Perihelion on the 3rd, when it is closest to the Sun.

Evening sky on Saturday January 2 looking east as seen from
Adelaide
at 21:00 ACDST.

Mercury is just above the horizon in the twilight. Similar views
will be seen elsewhere in Australia at the equivalent local time. (click
to embiggen).

Mercury falls back into the twilight. This will be the last week it is reasonably visible in the evening.

Jupiter enters the evening sky around midnight daylight saving time later this week.

On
the morning of New Years Day, if you are up celebrating, you will see
Jupiter and the waning Moon rise shortly before (non-daylight saving) or shortly after (daylight saving) midnight.

If you have bought binoculars or a low powered telescope to the New Years celebration you can see both the Moon and
Jupiter's moons (along with Jupiter) in the binocular or telescope field of view on New Years morning.

Jupiter and the Moon will be at their closest a couple of hours after
midnight, so if you have a long celebration it is well worth watching
the pair during the proceedings.

Telescopic view of the Moon and Jupiter, simulating the view through a
25 mm eyepiece on a 4" Newtonian Reflector at 2:30 pm daylight saving
time.

After New Years the Moon visits the rest of the planets (see below).

The evening is also graced by the summer
constellations of Taurus (with the V shaped cluster the Hyades forming
the head of Taurus the Bull and the beautiful Pleiades cluster nearby)
Orion the Hunter and Canis Major with bright Sirius, the dog star,
climbing above the eastern horizon.

Early morning sky on Thursday January 7 looking east as seen from
Adelaide
at 5:00 ACDST showing Mars, Venus, Saturn and the crescent Moon with the red star Antares close by. Similar views
will
be seen elsewhere in Australia at the equivalent local time. (click
to embiggen).

Jupiteris high in the morning skies and is rising before midnight by the end of the week.

Mars is higher in the morning skies and is readily visible in the pre twilight dark.

Venus is easy to see in the morning twilight. It is a distinct "gibbous Moon" shape and is nice in a small
telescope.

During the week Venus enters the head of the Scorpion and
continues to close in on Saturn. Venus, Saturn and the red star Antares
form a triangle low in the early twilight.

On the mornings of January 4th
Mars and crescent Moon are close, on the 7th, Venus Saturn and crescent
Moon are close and on the morning of the 9th, Venus and Saturn
spectacularly close (also visible together in a low power telescope).

Comet C/2013 US10 is a telescope
only object, and still difficult from the southern hemisphere. On the 1st and 2nd the comet is very close to the bight star Arcturus, making it easier to find in small scopes. From the northern hemisphere it is looking quite good in telescopes.

There are lots
of interesting things in the sky to view with a telescope. If you don't have a telescope, now
is a good time to visit one of your local astronomical societies open nights or the local planetariums.

Geomagnetic alert (30-31 December, 2015)

The Australian Space Weather Service (SWS ) has now issued a Geomagnetic Alert
for possible geomagnetic storms on 30-31 December UT from a earth facing CME.
Impact time is uncertain, but various ranges from 11 pm 30th AEDST to 5 am 31st
AEST have been predicted. A G3 storm (Planetary K index 7 or over) has been
predicted from the impact (probably 2 am is most likely).

There is a strong
possibility we will get unaided eye visible aurora in both Tasmania and the
Southern mainland, even possibly as far north as NSW/QLD border, based on
previous storms (and if the magnetic field of the storm has a favourable
orientation, this cannot be predicted in advance).

Evening skies are Moon free,
until around 11 pm daylight saving time, when a waning Moon rises. This is near
last quarter, which will not interfere too much with seeing aurora .

Dark
sky sites have the best chance of seeing anything, and always allow around 5
minutes for your eyes to become dark adapted.

As always look to the south for
shifting red/green glows, beams have been reported consistently over the last
few aurora and a large green "blob" has been seen, as well as bright proton arcs
and "picket fences".

The effect of a coronal mass
ejection that erupted in association
with the M1.8 flare (1245UT/28
December) may raise the geomagnetic
activity levels to major storm levels on
30 December and keep
the activity enhanced to minor storm levels on 31
December.

Friday, December 25, 2015

The Christmas Eve Asteroid 2003 SD220 is Not Nibiru (and will not cause Earthqaukes)

Location of asteroid 2003 SD220 at 5:00 am ACDST on Christmas morning as seen from Adelaide Australia, just after it's closest approach. Click to embiggen.

The Earth and Moon as seen from 2003 SD220 as simulated in stellarium.

Asteroid 2003 SD220, also known as the Christmas eve asteroid, will come close to Earth on 13:08 UT 24 December (that is 00:08 am AEDST in Australia) at distance of 0.073 AU. Visible only in high powered telescopes at closest approach, it has gained unwarranted attention from breathless articles in the tabloid press claiming that it could cause earthquakes (it won't, just like the other asteroids didn't). Various fringe sites have suggested it is, or is linked to, an imaginary planet called Nibiru (it''s not).

To put this in perspective, at its closest 2003 SD220 is around 28.4 Earth-Moon distances away this time. Yes, that is over 28 times the distance from the Earth to Moon (recall that the Apollo missions took 3 days to get to the Moon). As you can see from the image above, 2003 SD220 will only see the Earth and Moon as faint dots.

2003 SD220 is 1.8 kilometers in diameter (actually, it is quite elongated, image credit), too small and too far to have any gravitational effect on Earth. Consider that the Moon, orders of magnitude larger and 28 times closer, has negligible effects on earthqukaes, a 1.8 km dust mote is not going to have any effect. The asteroid comes close to us every couple of years or so, and hasn't had any effect in all the years it has passed us by.

As well, other large asteroids are being ignored favour of 2003 SD220. What about 2008 CM, a 1.5 km wide asteroid that will pass us by at 22 Earth-Moon distances on December 29. No one is claiming IT will cause earthquakes of is Nibiru.

So bottom line, 2003 SD220 will pass us by harmlessly, like all the other large asteroids we have been following.

For those of uswho just want to play around
with the asteroid orbit, or who want to argue with people who claim this
asteroid will hit us (it won't) I've made Celestia files for 2003 SD220.
As
usual, copy the data here to a plain text file (2003SD220.ssc) and copy the
file to the Celestia extras folder.

Thursday, December 24, 2015

There is still widespread angst that comet 2010 X1 Elenin will cause significant earthquakes when it comes close to Earth later this year.

I’ve shown previously that Elenin is not associated with earthquakes, however, in the comments (and on the intertubes), an as yet unpublished paper by Mensur Omerbashich titled “Astronomical Alignments as the Cause of ~M6+ Seismicity” http://arxiv.org/abs/1104.2036 is referenced. The paper purports to show that astronomical alignments, particularly that of Elenin, are the proximal cause of earthquakes of magnitude 6 or stronger. To save you time before you read the paper and my critique of it, I’ll give you a short and long summary.

The idea that gravitational influences could alter the frequency of earthquakes is plausible. The tidal bulge in the Earth (as opposed to the tidal bulge in the ocean) is about 30 cm, and a periodic flexing of the crust by 30 cm could indeed trigger earthquakes. Indeed, there is a weak correlation between the lithospheric tides associated with Full/New Moon and a subclass of shallow earthquakes (increasing the probability of this subclass of earthquakes by less than 1%).

On the 27th of February 2010, Elenin was beyond the orbit of Jupiter, but it is claimed that it had more tidal effect than bigger comets and asteroids closer to Earth.

However, tidal force drops of as the cube of the distance. The Sun is much more massive than the Moon, but the Moon has a bigger effect on Earth's tides because it is so much closer.

Venus has around the same mass as the Earth, and is the closest planet to us, but it produces roughly on ten millionth of the tidal force on Earth than the Moon does. If the Moon is not very effective at producing earthquakes, Venus sure won’t be (and invoking electrical or magnetic forces won’t work either, they fall off rapidly with distance too).

To assert that planetary alignments are a significant influence on earthquakes you will need some pretty strong evidence, does this paper supply it?

Coma confusion: You know the paper is not going to go well when it starts off with “..[Elenin] drags with it a cloud of gravitational locked particles around 30,000 Km across, making its gravitational shadowing significant …[page 1 para 4]”. Leaving aside the question of what “gravitational shadowing” is (it is never defined), Dr. Omerbashich is describing the coma of comet Elenin.

However, the coma is by no means “gravitationally locked” the particles in the coma are only loosely bound and are readily lost, the coma only appears stable because new dust particles are currently being added by outgassing from the comet.

Indeed, as I type Elenin’s coma is dispersing, as its dust production rate has dropped (possibly due to having exhausted a layer of volatiles, eg frozen carbon dioxide, below the comets crust). Also, while the coma is thick by interplanetary standards, from the point of view of Earth the coma is still a pretty good vacuum, with negligible mass compared to the parent comet.

Not only that, a coma is a feature of all comets that approach the Sun closely, for example comet 81P Wild had a coma of 50,000 Km and 103P Hartley had a coma of 150,000 Km. Because the coma is dynamic, produced as a comet heats up, at the early time points Omerbashich considers, Elenin’s coma would be much, much smaller.

What’s missing? The first thing that stands out when you read the paper is what is missing. All the classical planets, as well as Uranus and Neptune, are considered along with comet Elenin. But it’s obvious what is missing.

Where are all the Main Belt Asteroids? If you are going to consider a 4 Km wide frozen snowball, then large chunks of real estate like Ceres, Vesta (529 Km in diameter), Pallas and Juno should be considered as well.

And what about the 46 comets that reached perihelion in 2010, especially comets comparable to Eleinin such as Comet 81P wild, a comet of 4 km diameter with a 40,000 km coma, that came within 1.2 astronomical units (AU) of earth and comet 103P/Hartley, a 2 Km diameter comet with a 150,000 Km coma that came within 0.13 AU of Earth? Why aren’t they included if Elenin, which was more than 6 AU away for most of the year, is?

What’s also missing is the Moon, mostly. There are a few lunar alignments shown, and 14 of the 24 Full and New Moons are marked in table 1, but as the Moon is the closest, most important tidal object in our sky, the complete lack of 10 lunar encounters is significant.

Figure failureFigure 1, (section B shown below) purports to show the “resonance magnification pattern” as a “gravitational shadow” traverses the Earth.
What it in fact shows is a series of graphs of earthquake magnitude vs time. Each quake is shown equidistant from the others, regardless of the actual time separation between them. As well several points are left out, this greatly distorts the actual data.

For example graph B of figure 1 shows the series of earthquakes from 10 January to 12 January. It looks like a smoothly rising curve (possibly correlated with the “gravitational shadow”, whatever that is). However, only one magnitude 5.1 quake is shown, whereas there were many 5+ quakes in this time period. Also, the time point of 11 January is omitted even though there were no quakes of 5+ in this period of time (the other graphs have similar issues). This makes the curve look quite different from reality.

This graph shows how it should have been done (click to embiggen). I have plotted quake magnitude vs Julian Day number since 8 January for the interval between 9 January and 14 January, (full Julian day numbers make the graph unreadable), UT times of earthquake occurrence being rounded to the nearest half hour for conversion to Julian dates.

During these dates Venus was a degree or closer to the Sun (Omerbashich never really gives a numerical criterion for what constitutes an alignment). I have also plotted the tidal force due to Venus at the time of each earthquake (Calculated from the formula below using Excel, planetary masses and distances from SkyMap and earthquake magnitude from here), it is falling over this period as Venus is moving away from the Earth.

You can see that this graph is very different to the one that Omerbashich provides, and refutes Omerbashich’s claims. Now this is just one graph out of a whole bunch, but each one has similar, fatal flaws. They all show M+6 events evenly spaced, regardless of when they occurred, and omit relevant 5+ events. When a 5+ event is included, it is to anchor a graph and give a misleading impression of a smooth curve.

As the tidal effect is actually due to the Sum of the tidal force of Venus and the Sun, I also show a graph with the Sum of the Venus Sun tidal forces (again, click to embiggen). You can see that they are going down. This is mostly due to the earth moving away from the Sun post perihelion, as the tidal force of Venus is one ten millionth of that of the Sun, it doesn’t register in this graph.

Statistics revisited Table 2 of the paper purports to show all M6+ earthquakes in relation to various alignments (it doesn’t, but the discrepancies are minor, just an example of sloppiness). It looks kind of impressive, until you think about it. All Omerbashich is doing is lining up instances of events with earthquakes. Using this method I can show that my family eating pizza causes earthquakes.

On March 4 I had pizza, and there was a M6.5 Earthquake, and again on March 11 (an impressive M6.9 quake) and on March 25 (only M6.6, but there was an M7.5 earthquake when we had pizza on June 16). All in all, 20 times when we had Pizza there was a magnitude 6 or greater quake (actually, we had pizza more times than that, but those are the times that I have dates and UT times for).

Apart from the physical implausibility of my family chowing down on pizzas causing earthquakes (well maybe my increase in weight could do it), how can we determine if eating pizza causes earthquakes? Statistics is how.

In 2010 there were 156 earthquakes of magnitude 6 and over. In 2010 we had pizza 48 times. If the earthquakes were occurring at random with respect to our eating pizza, then we would expect an M6+ earthquake to occur on a day we ate pizza 21 times, and we observed 20 earthquakes on days we ate pizza. Therefore we can conclude there is no connection between us eating pizza and earthquakes (physical implausibility aside).

So, what about the planetary alignments and the earthquakes? The most plausible astronomical source of earthquakes is the Moon, which causes the strongest lithospheric tides. There were 24 full or new Moons in 2010. This is where the Sun and Moon are aligned and we get the strongest tides, which might have a chance of producing earthquakes (or triggering ones that were just about to go anyway).

In 2010 there were 12 earthquakes that corresponded to a full or new Moon. By chance alone, we would expect 10 earthquakes to correspond to the full or new Moon, which is not significantly different from what we observe. We can do a double check, if the alignment idea is correct, then there should be more earthquakes during the full/new Moon (when the tides are highest) than during first and last quarter (where the tides are lowest).

In fact there were 16 earthquakes during first and last quarter Moons compared to 12 during full/new Moon. Thus the idea that lunar alignments are a significant source of earthquakes is disproven. Actually, e have one more trick up our sleeve, I took all M6+ earthquakes from 2000-2010 and did a Fourier transform on it. If the Moon played a significant role, we should have seen a peak corresponding to the interval between full and new Moons. But we don’t, or any other peak corresponding to an astronomical alignment.

This pretty much eliminates all evidence of astronomical alignments playing a significant role in earthquakes.

Omerbashich spends a lot of space on alleged Elenin alignments, but it's just the pizza gambit again. The plausibility of Elenin being responsible for any earthquakes is very low. If the Moon can’t produce significant numbers of earthquakes above baseline activity then Elenin, with a tidal force of less than a billionth of that of the Moon, is not a plausible candidate for producing earthquakes. Again, completely ignores comet 81P (which had a thousand times more tidal force than Elenin) and comet 103P/ Hartley (which had a million times more tidal force than Elenin at its closest approach to Earth). 103P is pretty much devoid of association with earthquakes.

The rest of the paper is pretty much cherry picking figures. Figure 2 basically shows that the occurrence of M8+ earthquakes is pretty random, but Omerbashich claims this shows that comet Elenin (a 4 Km chunk of dirty ice) has been influencing earthquakes since 2007 (when it’s tidal force was a trillionth of that of the Moon). Yet somehow, mysteriously all the other, closer comets (including much bigger ones, like 2006 P1) had no effect.

Conclusion Omerbashich’s paper, “Astronomical Alignments as the Cause of ~M6+ Seismicity” is a poor paper, with inadequate and misleading data analysis, and which misunderstands basic physics and cometary nature. It provides no evidence that Elenin is involved in earthquakes.

Postscript: at this site, it was claimed that planetary alignments as predicted by Omerbashich would produce big earthquakes on 23 May 2011, 23 (and 24) May have come and gone, with only a couple of magnitude 5 quakes, fairly quite days really. Dr. Omerbashich's web site claims 9-19 May as a time of intensified 6+ quakes. It wasn't.

Post-postscript: I've beening trying to think of a really simple way to get the scale differences between Eelnin and the other objects in the solar system that people can grasp easily.

Dr. Omerbashich likens his resonator effect to that of a group of soldiers marching in lockstep across a bridge, causing damaging resonances in the bridge. Well, imagine the Moon is a 70 Kg soldier marching along, behind the soldier is an ant marching. Do you think the ant will add to the resonance produced by the soldier? No, the mass of the ant is far too small. AND that ant is 10 times more massive in relation to the soldier than Elenin is to the Moon.

Disclaimer: small portions of the original paper, less than 1% of that work, are quoted with appropriate citation and links to the original under the fair use provisions of the copyright act for the purpose of criticism, comment, news reporting, teaching
(including multiple copies for classroom use), scholarship, or research.

Wednesday, December 23, 2015

The Sky This Week - Thursday December 24 to Thursday December 31

The Full Moon is Friday December 25. Mercury is low in the evening sky. Jupiter, Venus and
Mars form a line in the morning sky and are joined by Saturn. Mars is close to the bright star Spica on the 25th. Venus comes closer to Saturn. Comet C/2013 US10
Catalina is higher in the morning sky.

The Full Moon is Friday December 25. This is the first full Moon to fall on Christmas Day since 1977.

Evening sky on Saturday December 26 looking east as seen from
Adelaide
at 21:15 ACDST. Mercury is just above the horizon in the late twilight. Similar views
will be seen elsewhere in Australia at the equivalent local time. (click
to embiggen).

The early evening sky is now graced by Mercury low in the late evening
twilight. Jupiter enters the evening sky in late December.

The evening is also graced by the summer
constellations of Taurus (with the V shaped cluster the Hyades forming
the head of Taurus the Bull and the beautiful Pleiades cluster nearby)
Orion the Hunter and Canis Major with bright Sirius, the dog star,
climbing above the eastern horizon.

Early morning sky on Friday December 25 looking east as seen from
Adelaide
at 5:00 ACDST showing Jupiter, Mars, Venus, Saturn and comet C/2013 US10. Similar views
will
be seen elsewhere in Australia at the equivalent local time. (click
to embiggen).

Jupiterrises higher in the morning skies and is now easy to see in the pre-dawn dark.

Mars is higher in the morning skies and is visible in the early twilight.

Venus is easy to see in the morning twilight. It is a distinct "gibbous Moon" shape and is nice in a small
telescope.

Saturn returns to the morning sky. You will need a clear, level horizon to see it effectively at the beginning of the week.

Jupiter, Mars, Venus, Saturn and the bright stars Regulus
and Spica form a
line
in the sky this week. Mars starts the week close to the bright star Spica, and while it is closest on the morning of the 24th, on the morning on the 25th it is less than 10 arc seconds further away, and will still look close.

During the week Venus heads towards the head of the Scorpion, and Saturn. By the end of the week Venus, Saturn and the red star Antares form a triangle low in the early twilight.

Comet C/2013 US10 is a telescope
only object, and still difficult from the southern hemisphere. However,
from the northern hemisphere it is looking quite good in telescopes.

The Christmas Moon rises on the 25th under the constellation of Orion, with Taurus,
the Pleiades and Canis Major nearby. This shows the north-eastern
horizon at around 10:00 pm local daylight saving time. (click
to embiggen).

If beautiful Christmas morning planets are not enough, Christmas evening is rather special.

The rising full moon is the first Christmas Full Moon since 1977, a gap
of 38 years. The next will not be until 2034, 19 years later.

There are lots
of interesting things in the sky to view with a telescope. If you don't have a telescope, now
is a good time to visit one of your local astronomical societies open nights or the local planetariums.

Tuesday, December 22, 2015

While not much spectacular is going on in the Southern Hemisphere skies, Christmas day will see the first Christmas Full Moon for 38 years and Mars and the bright star Spica close in the morning skies.

Early morning sky on Friday December 25 looking east as seen from
Adelaide
at 5:00 ACDST showing Jupiter, Mars, Venus and comet C/2013 US10. Similar views
will
be seen elsewhere in Australia at the equivalent local time. (click
to embiggen).

If
you are one of being Santa's
Helpers and are up in the early morning on the 25th around 5 am distributing presents and helping Santa eat all those biscuits, then you will see 4 bright planets, Jupiter, Mars, Venus (and if you
have a level horizon) Saturn.

As an added bonus on Christmas morning
Mars and the Bright star Spica are at their closest (strictly speaking, they were at their closest on Thursday, but what is a mere 0.01 arc minutes between friends.

The Christmas Moon rises under the constellation of Orion, with Taurus, the Pleiades and Canis Major nearby. This shows the north-eastern horizon at around 10:00 pm local daylight saving time. (click
to embiggen).

If the beautiful morning planets are not enough, the evening is rather special.

As you are contemplating your evening barbie and Christmas pud, the rising full moon is the first Christmas Full Moon since 1977, a gap of 38 years. The next will not be until 2034, 19 years later.

Put it another way, the last time we had a full Moon on Christmas, the first Star Wars movie "A new Hope" was playing in cinemas, this Christmas Full Moon sees "The Force Awakens".

While this is a long time between Full Moons, there are much longer gaps. People had to wait 57 years from 1920 to 1977's Christmas Full Moon.

And Christmas is not special, December 23 will see only 3 Full Moons between 1900 and 2100, with gaps of 19, 46 and 76 years between full Moons. September 3 and May 24 only saw 3 Full Moons too. Indeed, if you saw the Full Moon on May 24, 1956, you will have to wait 133 years until 2089 to see the next Full Moon on May 24.

Exactly why there are these long gaps, I do not know. As the time from Full Moon to Full Moon is 29.5 days, whereas the months are 30-31 days (Excepting February, which is 28, and 29 in leap years), the date of the full Moon will slowly drift over the course of the year.

Typically, it takes 19 years for a Full Moon to fall on the same date again, however, gaps can occur in multiples of 19 (133 is 7 x 19 and 114 is 6x 19), but I'm not sure why. There are also weird fractions of 19 (46 years is 2.42 x 19). Again, I have no idea why this is.

After Christmas, New Years holds a small celestial treat.

On
the morning of New Years Day, if you are up celebrating, you will see
Jupiter and the waning Moon rise shortly before (non-daylight saving) or shortly after (daylight saving) midnight.

If you have bought binoculars or a low powered telescope to the New Years celebration you can see both the Moon and
Jupiter's moons (along with Jupiter) in the binocular or telescope field of view on New Years morning.

Jupiter and the Moon will be at their closest a couple of hours after midnight, so if you have a long celebration it is well worth watching the pair during the proceedings.

Telescopic view of the Moon and Jupiter, simulating the view through a 25 mm eyepiece on a 4" Newtonian Reflector at 2:30 pm daylight saving time.

After New Years the Moon visits the rest of the planets.

On the mornings of January 4th
Mars and crescent Moon are close, on the 7th, Venus Saturn and crescent
Moon are close and on the morning of the 9th, Venus and Saturn
spectacularly close (also visible together in a low power telescope).

The line-up of Jupiter, crescent Moon, Mars and Venus as seen from
Adelaide on the morning of 7 January at 5:00 am. (click to embiggen)

There is currently a
planetary index of 6, but this is in daylight, it is likely that G1 storm
conditions may persist until after sunset. The NOAA site has a predicted G1/G2
storm for tonight. IF the current conditions do persist until after twilight,
there is a strong possibility we will get unaided eye visible aurora in both
Tasmania and the Southern mainland based on yesterdays events,. Evening skies
have a waxing Moon, which will interfere a bit with seeing aurora (it didn't
interfere that much last night).

Dark sky sites have the best chance of
seeing anything, and always allow around 5 minutes for your eyes to become dark
adapted.

As always look to the south for shifting red/green glows,beams have
been reported consistently over the last few aurora and a large green "blob" has
been seen, as well as bright proton arcs and "picket fences".

A significant
geomagnetic storm has been in progress for the past 24hours. Bright auroras
at multiple wavelengths were visible in Tasmaniaon the night of Dec 20.
Aurora may again be visible in Tasmania andpossibly Southern Victoria on the
night of Dec 21 if geomagneticactivity persists at present levels into local
night hours. Prevailingbright moonlight may hinder observation. Aurora
alerts will followshould favourable space weather activity
eventuate.

Friday, December 18, 2015

Aurora Watch and Geomagnetic alert (18-19 December)

The Australian Space Weather Service (SWS formerly the IPS) has now issued a Geomagnetic Alert an Aurora Watch for possible aurora on 18-19 December UT from
a CME impact (this translates to early the 19th to probably late 19th early
20th). The NOAA site has a predicted G1 storm for 18 Dec (UT, morning 19 Dec
AEDST) and a G2 storm for 19 Dec (UT, 19-20 Dec AEDST).

In the last geomagnetic
storm activity was seen form 9:30-11:30 pm, in previous storms the best views
were from 11:30 pm - 12:30 am but there was activity the following day. There is
a strong possibility we will get unaided eye visible aurora in both Tasmania and
the Southern mainland based on previous events, IF the CME impact occurs outside
of daylight hours. Evening skies have the first quarter Moon, which should not
interfere too much with seeing aurora.

Dark sky sites have the best
chance of seeing anything, and always allow around 5 minutes for your eyes to
become dark adapted.

As always look to the south for shifting red/green
glows,beams have been reported consistently over the last few aurora and a large
green "blob" has been seen, as well as bright proton arcs and "picket fences".

SUBJ: IPS
AURORA WATCHISSUED AT 0025 UT ON 18 Dec 2015 BY IPS RADIO AND SPACE
SERVICESFROM THE AUSTRALIAN SPACE FORECAST CENTRE

A Coronal Mass
Ejection sequence is expected to impact the Earth lateon the UT day Dec 18
to early Dec 19, possibly resulting insignificant space weather activity and
visible auroras during localnighttime hours. Based on expected arrival times
the most significantspace weather activity may occur during local daylight
hours in theAustralian region. Aurora alerts will follow should favourable
spaceweather activity eventuate.

Wednesday, December 16, 2015

Southern Skywatch December, 2015 edition is now out!

The line-up of Jupiter, crescent Moon, Mars and Venus as seen from
Adelaide on the morning of 8 December at 5:0 am. (click to embiggen)

The December edition of Southern Skywatch is now up. This month features still more nice planetary action
. Unfortunately, most of it is in the early morning with Venus, Mars
and Jupiter
forming a line in the morning sky with the crescent Moon joining them.

Jupiter climbs higher in the morning sky and has close encounters with the crescent Moon.

Mars is visible in the early morning sky and has close encounters with SPica and the crescent Moon.

Tuesday, December 15, 2015

The Sky This Week - Thursday December 17 to Thursday December 24

The First Quarter Moon is Saturday December 19. Mercury climbs higher in the evening sky. Jupiter, Venus and
Mars form a line in the morning sky. Mars is close to the bright star Spica on the 24th. Comet C/2013 US10
Catalina is higher in the morning sky.

The First Quarter Moon is Saturday December 19. The Moon is at perigee, closest to the Earth, on the 21st. Earth is at solstice, when the day is longest, on the 22nd.

Evening sky on Saturday December 19 looking east as seen from
Adelaide
at 21:15 ACDST. Mercury is just above the horizon in the late twilight. Similar views
will be seen elsewhere in Australia at the equivalent local time. (click
to embiggen).

The early evening sky is now graced by Mercury low in the late evening twilight. Jupiter enters the evening sky in late December.

The evening is also graced by the summer
constellations of Taurus (with the V shaped cluster the Hyades forming
the head of Taurus the Bull and the beautiful Pleiades cluster nearby)
Orion the Hunter and Canis Major with bright Sirius, the dog star,
climbing above the eastern horizon.

Early morning sky on Thursday December 24 looking east as seen from
Adelaide
at 5:00 ACDST showing Jupiter, Mars, Venus and comet C/2013 US10. Similar views
will
be seen elsewhere in Australia at the equivalent local time. (click
to embiggen).

Jupiterrises higher in the morning skies and is now easy to see in the pre-dawn dark.

Mars is higher in the morning skies and is visible in the early twilight.

Venus is easy to see in the morning twilight. It is a distinct "half Moon" shape and impressive in a small
telescope.

Jupiter, Mars, Venus and the bright stars Regulus
and Spica form a
line
in the sky this week. Mars comes closer to the bright star Spica, and is closet on the morning of the 24th.

Comet C/2013 US10 is a telescope
only object, and still difficult from the southern hemisphere. However, from the northern hemisphere it is looking quite good in telescopes.

There are lots
of interesting things in the sky to view with a telescope. If you don't have a telescope, now
is a good time to visit one of your local astronomical societies open nights or the local planetariums.

Friday, December 11, 2015

Geminid Meteor Shower 14-15 December 2015

The northern horizon at 4:00 am ACDST as seen from Adelaide on Tuesday December 15. The Geminid radiant is marked with a starburst. Similar views
will
be seen elsewhere in Australia at a similar latitude and the equivalent local time. (click
to embiggen).

The
northern horizon at 3:00 am AEDST as seen from Sydney on Tuesday
December 15. The Geminid radiant is marked with a starburst. Similar views
will
be seen elsewhere in Australia at a similar latitude and the equivalent local time. (click
to embiggen).

The Geminids are
unusual meteor shower in that their parent body is 3200 Phaethon, an asteroid, rather
than a comet. It is speculated though that Phaeton is actually a "gassed
out" comet, and so the debris that makes up the Geminids may still be
cometary particles. The Geminids are a fairly reliable meteor shower and this
year moonlight will not interfere, and some decent meteors rates should be seen.

Unlike the Leonids, where there is a
very narrow peak of high activity, the Geminids have a broad
peak and will show good activity well before and after the peak, and on
the day before and after. The peak is December 14, 18h00m UT. That is 5 am AEDST December 15 in Australia. This is in twilight in most of Australia, but levels should be ramping up before twilight so you should get decent rates. However, the radiant doesn't rise until just
before midnight (daylight saving time) in most of Australia, so you will
still have to disturb your sleep for this one.

Australians should see
a meteor every two to three minutes under dark skies in the early
morning of the 15th, between 1:00 am and 4:00 am local daylight saving time. You can
find predictions for your local site at the meteor flux estimator (choose 4 Geminids and date 14-15 December, don't forget to change the date to 2015).

At
1.00 am in the morning AEDST (midnight, AEST) Castor (alpha Geminorum)
is about two hand-spans above the horizon and 10 hand-spans to the right of
due north. Pollux, the other twin, is less than a hand-span to the right
again. The radiant is just below Pollux.

When you get up, allow at least 5
minutes for your eyes to adjust and become dark adapted (even if you
have stumbled out of bed in the dark, here's some hints on dark adaption
of your eyes so you can see meteors better) and be patient, it may be
several minutes before you are rewarded with you first meteor, then a
couple will come along in quick succession (a meteor every three minutes
is an average, they won't turn up like a ticking clock but more or less
randomly).

Choose a viewing spot where you can see a large swathe
of sky without trees or buildings getting in the way, or with street
lights getting in your eyes. The darker the spot the better (but
do be sensible, don't choose a spot in an insalubrious park for
example). While the radiant is where the meteors appear to originate
from, most of the meteors will be seen away from the radiant, so don't
fixate on the radiant, but keep your eye on a broad swath of sky
roughly centred just above the radiant (as the radiant doesn't rise very
high, looking exactly at the radiant will mean you miss some higher
up).

A lawn chair or something similar will make your observing
comfortable (or a picnic rug spread on the ground and a nice pillow),
and having a Thermos of hot coffee, tea or chocolate to swig while
watching will increase your comfort. Despite it being summer, make sure
you have a jumper or something as the night can still get cold

Wednesday, December 09, 2015

The Sky This Week - Thursday December 10 to Thursday December 17

The New Moon is Friday December 11. The crescent Moon is close to Mercury
on the 13th. Jupiter, Venus and
Mars form a line in the morning sky. Venus is close to comet C/2013 US10 Catalina. Geminid meteor shower on the morning of the 15th.

The New Moon is Friday December 11.

Evening sky on Sunday December 13 looking east as seen from
Adelaide
at 20:45 ACDST. Mercury and the crescent Moon are just above the horizon in twilight. Similar views
will be seen elsewhere in Australia at the equivalent local time. (click
to embiggen).

The evening sky is now graced briefly by Mercury (well the twilight actually this week). Jupiter enters the evening sky in later December.

But while the evening is devoid of bright planets (aside, breifly, from Mercury), the summer
constellations of Taurus (with the V shaped cluster the Hyades forming
the head of Taurus the Bull and the beautiful Pleiades cluster nearby)
Orion the Hunter and Canis Major with bright Sirius, the dog star,
climbing above the eastern horizon.

Early morning sky on Saturday December 12 looking east as seen from
Adelaide
at 5:00 ACDST showing Jupiter, Mars, Venus and comet C/2013 US10. Similar views
will
be seen elsewhere in Australia at the equivalent local time. (click
to embiggen).

Jupiterrises higher in the morning skies and is now easy to see in the pre-dawn dark.

Mars is higher in the morning skies and is visible in the early twilight.

Venus is easy to see in the morning twilight. It is a distinct "half Moon" shape and impressive in a small
telescope.

Jupiter, Mars, Venus and the bright stars Regulus
and Spica form a
line
in the sky this week. The waning Moon joins the line-up making for some
very nice morning sights with The Moon visiting Jupiter, Mars and then
Venus.

Comet C/2013 US10 joins the line-up. It is much
fainter than anticipated and at magnitude 6.4 and fading, and being low to the
horizon, it is probably a telescope
only object.

The northern horizon at 4:00 am ACDST as seen from Southern Australia
(northern Australia is similar but Gemini and the radiant is higher in
the sky) on Tuesday December 15. The Geminid radiant is marked with a starburst . Similar views
will
be seen elsewhere in Australia at the equivalent local time. (click
to embiggen).

The Geminids are a fairly reliable meteor shower and this
year moonlight will not interfere.

Unlike the Leonids, where there is a
very narrow peak of high activity, the Geminids have a broad
peak and will show good activity well before and after the peak, and on
the day before and after.

The radiant doesn't rise until just
before midnight (daylight saving time) in most of Australia, so you will
still have to disturb your sleep for this one. Australians should see
a meteor every two to three minutes under dark skies in the early
morning of the 15th, between 1:00 am and 4:00 am local time. You can
find predictions for your local site at the meteor flux estimator (choose 4 Geminids and date 14-15 December, don't forget to change the date to 2015).

At
1.00 am in the morning AEDST (midnight, AEST) Castor (alpha Geminorum)
is about two hand-spans above the horizon and 10 hand-spans to the right of
due north. Pollux, the other twin, is less than a hand-span to the right
again. The radiant is just below Pollux.

As well, Orion and the
Hyades will be visible and bright Jupiter, Mars and Venus will be nearby. So it will be a
quite nice morning for sky watching. Keep an eye out for satellites!

There are lots
of interesting things in the sky to view with a telescope. If you don't have a telescope, now
is a good time to visit one of your local astronomical societies open nights or the local planetariums.

Thursday, December 03, 2015

Morning sky on Friday December 4 looking east as seen from
Adelaide
at Nautical twilight (4:50 ACDST) showing the waning Moon, Jupiter, Mars, and Venus, and comet C/2013 US10. Similar views
will
be seen elsewhere in Australia at the equivalent local time. (Nautical twilight, click
to embiggen).

Morning sky on Saturday December 5 looking east as seen from
Adelaide
at Nautical twilight (4:50 ACDST) showing Jupiter, the waning Moon, Mars, and Venus, and comet C/2013 US10. Similar views
will
be seen elsewhere in Australia at the equivalent local time. (Nautical twilight, click
to embiggen).

Morning sky on Sunday December 6 looking east as seen from
Adelaide
at Nautical twilight (4:50 ACDST) showing Jupiter, Mars, the crescent Moon, Venus, and comet C/2013 US10. Similar views
will
be seen elsewhere in Australia at the equivalent local time. (Nautical twilight, click
to embiggen).

Morning sky on Monday December 7 looking east as seen from
Adelaide
at Nautical twilight (4:50 ACDST) showing the Jupiter, Mars, the crescent Moon, Venus, and comet C/2013 US10. Similar views
will
be seen elsewhere in Australia at the equivalent local time. (Nautical twilight, click
to embiggen).

Morning sky on Tuesday December 8 looking east as seen from
Adelaide
at Nautical twilight (4:50 ACDST) showing Jupiter, Mars, Venus, the crescent Moon, and comet C/2013 US10. Similar views
will
be seen elsewhere in Australia at the equivalent local time. (Nautical twilight, click
to embiggen).

Morning sky on Tuesday December 8 looking east as seen from Brisbane
at Nautical twilight (3:47 AEST) showing Jupiter, Mars, Venus, the crescent Moon, and comet C/2013 US10. (click
to embiggen). Compare to the view from Adelaide.

Over the next few days the morning skies will host a gorgeous sight as the waning, then crescent, Moon skips down the bright planets (and the bright star Spica) from the 4th to the 8th of December. As well comet C/2013 US10 Catalina is in a good position to be seen in the morning twilight, although it will be hard to see in the twilight.

Location map of comet C/2013 US10 Catalina suitable for printing. The large circle is the field of view of 10x50 binoculars, the small that of a 24 mm telescope eye piece. Click to embiggen and print.

For the next few days the location of comet Catalina is fairly easy to find. Sweeping down ad east of Venus brings you to Kappa Vriginis (K on the map) a moderately bright star, the comet is within a binocular field of K Virg.

Unfortunately, with twilight advancing and the comet low on the horizon, it is unlikely to be visible in binoculars, despite it being around magnitude 6, and you will probably have to star hop down from K Virginis with a telescope.

Enlarged map showing the location of comet C/2013 US10 Catalina suitable for printing. Use the top map for orentation, then this one to guide star hoping. The large circle is
the field of view of 10x50 binoculars, the small that of a 24 mm
telescope eye piece. Click to embiggen and print.

Northern Australia (Brisbane and anywhere north of it) has the best views with the comet being 2-3 hand-spans above the horizon at Nautical twilight (an hour before sunrise).

In Darwin and Alice Springs the comet is even visible around a hand-span above the eastern horizon at Astronomical twilight (an hour and a half before sunrise). For places south of Brisbane the comet is only a hand-span above the horizon at Nautical twilight. Tasmania the comet is even lower.

The climax of this weeks planet dance is on the 8th, when the Moon and Venus are close, and the comet just below them. There have been some great images of the comet coming from Europe, where the comet is much higher in the sky. We are unlikely to see more than a fuzzy blob in our telescopes, but it s worth the hunt.

Wednesday, December 02, 2015

The Sky This Week - Thursday December 3 to Thursday December 10

The Last Quarter Moon is Thursday December 3. Jupiter, Venus and
Mars form a line in the morning sky. The waning Moon is close to Jupiter on the 4th. The crescent Moon is close to Mars on the 6th and the crescent Moon is close to Venus and comet C/2013 US10 Catalina on the 8th.

The Last Quarter Moon is Thursday December 3.

Evening sky on Saturday December 5 looking east as seen from
Adelaide
at 21:00 ACST. The beautiful cluster the Pleiades, the Hyades and Orion . Similar views
will be seen elsewhere in Australia at the equivalent local time. (click
to embiggen).

The evening sky is now devoid of bright planets until late December, when Mercury and Jupiter enter the evening sky.

But while the evening is devoid of bright planets, the summer
constellations of Taurus (with the V shaped cluster the Hyades forming
the head of Taurus the Bull and the beautiful Pleiades cluster nearby)
Orion the Hunter and Canis Major with bright Sirius, the dog star,
climbing above the eastern horizon.

Early morning sky on Tuesday December 8 looking east as seen from
Adelaide
at 5:00 ACDST showing Jupiter, Mars, and Venus, The crescent Moon and comet C/2013 US10. Similar views
will
be seen elsewhere in Australia at the equivalent local time. (click
to embiggen).

Jupiterrises higher in the morning skies and is now easy to see in the pre-dawn dark.

Mars is higher in the morning skies and is visible in the early twilight.

Venus is easy to see in the morning twilight. It is a distinct "half Moon" shape and impressive in a small
telescope.

Jupiter, Mars, Venus and the bright stars Regulus
and Spica form a
line
in the sky this week. The waning Moon joins the line-up making for some very nice morning sights with The Moon visiting Jupiter, Mars and then Venus.

Comet C/2013 US10 joins the line-up. It is much
fainter than anticipated and at magnitude 6.1, and being low to the
horizon, it is probably a telescope
only object. However, on the 8th it is below Venus and the thin crescent Moon, and may be visible in good binoculars.

There are lots
of interesting things in the sky to view with a telescope. If you don't have a telescope, now
is a good time to visit one of your local astronomical societies open nights or the local planetariums.